This is a very common question for new users. As with everything in the world of hair replacement (or so it would seem), there is never a "cut and dry" answer. The life of your system- no matter what base you use, will depend on many different factors, such as how you care for the system, how you wear/attach the system, etc.
As you can see when you view many of our different lace bases, it would be unusual for a full lace base to last longer than about 4 months or so. However, I do want to note that with proper and diligent care, lace systems can last much longer. Lace and poly are two very different materials.
Lace will tend to provide a much more natural appearance, typically be more comfortable (breathable), and if you plan to use Hollywood lace, the material will be very soft and light.
How to clean lace base?
The solvent soak is one of the most popular cleaning methods for lace bases. Lace material is so delicate that you should be careful not to soak it too long, no matter which solvent you are using. If the lace base is placed in the solvent, it can cause the knots to swell, which will lead to premature shedding. Additionally, you also need to be careful not to use too many solvents. The solvent which submerges the underside of the base is enough. Too much solvent will lead to the tangled and matted hair.
When it comes to removing the adhesive residues on the lace bases, you need to use as little tension/pressure on the base as possible. If you put too much tension on the base when scraping off the adhesive residue, you will risk causing the system to fray too quickly or you could end up tearing the hair system.
With a lace base, it is really essential to remove the system before the bond had completely broken down. As it breaks down, it gets gooey and tends to work its way up through the lace and into the hair which makes a complete mess to clean up.
When rinsing a lace system, it is very important that you rinse the system with the underneath side of the base facing up, meaning that the water is hitting the lace first and running down through the lace onto the hair. This will prevent the hair from irreversibly pulling back through the base.
NO matter what base material you choose, you have to ensure that there is no solvent left on the base before reattaching the system. If you don't get all of the solvent and adhesive residue off of your base, it can prevent the new tape or adhesive from adhering properly.
Poly, however, will provide you far more durability, and can also handle a much heavier density than most lace systems can. If a visible front hairline area isn't important to you, then poly can look incredibly natural.
How to clean poly base?
Poly/skin base is much easier to clean up than lace base. Most people who use poly/skin base for extended wear will use red liner tape on the poly before placing the stronger tape or adhesive. Although this does not affect the hold in any way, it does make the cleanup much easier.
When people use red liner tape which will only adhere to poly, they just need to gently peel it off of the base along with the tape or glue on top of it. There will be very minimal adhesive residue, if any, left on the base for cleaning. (Red liner tape cannot be used with lace bases.
When it comes to making choices about base materials, you may want to ask yourself, "is it more important for me to have a durable base or a natural-looking base.